I searched the archived topics but there was no reply to this question.. When gravity bleeding back brakes.. i'm replacing the caliper so I'm starting out with an empty caliper.. The current calipers have two bleeders on the top side of the caliper and a plug on the bottom outside.. brake line on the bottom inner side.. Will gravity fill up the caliper and force fluid out the top bleeder? Do the outer bleeder first then the inner or both at the same time. I was going to get the wife to pump the peddle but first off I have the seats out working on the carpets so I'd have to temp install them.. then the cars up on jack stands so I don't want her climbing around in there.. and then I'll have to do something for her as payback.. :)

 

I don't know if there's a "correct" way or not. I crack one of the bleeders, and put a piece of clear tubing over the nipple....and run the tubing into a jar. Make sure the MC is full. Then I go about my business, and keep an eye on it till I see fluid in the tubing. Then, I do the other bleeder. After I'm done, I'll usually "borrow" the wife or a friend to do the "pump, hold" routine. Since the MC is above the caliper, and fluid flows downhill, the caliper will fill. Chuck

 

The way i do it is with a piece of clear plastic hose fitted on the end of the bleeder nut and drained into break fluid bottle make sure end of hose is in the fluid open the nut and pump five or six times to bleed the lines.

 

I think the gravity thing will only work if the front end is significantly higher that the rear. The old two man- you pump while I wrench is still my preferred method. On that note, you don't have to sit in the car to pump the brakes if you are limber and have the ability to stand on one foot without falling over. :jester

 

A quick way I have found to work is to use a A/C vacumn pump, adapt the line to fit onto the bleeder, open the bleeder and let the pump do the work. This is a fast, one man way of pulling all the air out of the system. Start with the furtherest caliper away from the master cylinder and then work towards the drivers front (closest one).

 

Also, i've heard of the old broom or 2x4 bit, pumping the brakes from the rear yourself and bleeding them.. not like the rear wheel is that far away from the pedal :)

 

Gravity bleeding definately works and works well. I don't use a tube on the bleeder because it's harder to see air come out of it. I watch it till there is fluid coming out, that means that the caliper has filled up with fluid. At that point, you will want to top off the master cylinder. Then continue to watch till you don't see any interuptions in the flow. For every interuption, there is an air bubble. Once you have a clean flow from the inner, close it and do the outer. Again, wait till you have a clean uninterupted flow and close the bleeder. Then I go around to the left rear and repeat the process then to the right front, then the left front. Once I have done this at all 4 corners, I start again at the right rear, open the inside bleeder and tap on the caliper with a wooden mallet. You will see air interupting the flow. By tapping, not hard but hard enough to dislodge any air bubbles in the caliper, you will be able to get all the air out. Once you have done this, repeat for the outer bleeder. Then go to the left rear, right front, and finish with the left front. With this done, you should have a good peddle. Make sure you always have fluid in the master cylinder or you will have to start all over. Also, you may want pump the brakes, hold it and loosen the front line on the master cylinder, then repeat for the rear line. You can accomplish this by yourself. This insures that no air bubbles remain in the master cylinder if it has gone dry at some point.

Hope this helps.

dl

 

OK.. I'm doing this gravity brake bleeding and I realized I don't have any patience.. It's been a while and not much fluid had drained from the master cylinder. I replaced the drivers side rear caliper so there's a lot of fluid that has to fill it up and it's moving but.. well.. not fast enough.. :lol: Would one of those pumps you attach to a drill work? What type of A/C pump are you using and where did you get it.. I don't have either and I'm going to let it gravity bleed while I'm working from home today but sounds like a better deal for future brake bleeds..

 

Koz,

The problem with pumps is that they suck air from around the threads of the bleeder screw. After you use the pump, you still have to let gravity do it's thing. Be patient, it will pay off here. In my experience, you should be getting enough flow to empty the rear chamber of the master cylinder in about 15 minutes or so. If you are only getting a drop or two, there is a clog somewhere. Put a piece of hose on the bleeder screw and run it into a bottle or pan. Then SLOWLY depress the brake peddle with the bleeder open. This will force the fluid out. Then proceed with gravity bleeding as outlined above.

Post back if you have any problems.

dl

 

It's taking a lot longer than that.. It's been over an hour with no fluid.. Should I put the cover on the master cylinder before touching the brake pedal?

 

Definately. You don't have to strap it down, just lay it on there in it's normal position. Pump the pedel once or twice till you see that you have gotten fluid out then top off the master cylinder, remove the hose, and see if you start getting fluid out. You do need to remove the top of the master cylinder again after doing this. A vacuum can build up causing fluid not to flow.
dl


[Modified by dladd74roadster, 8:41 AM 3/29/2002]

 

So I put the cover on the master cylinder and brake fluid overflows over the edge.. that sucked.. Resessed the rubber booties and put the cover on.. I pushed the pedle a couple time and I got fluid dripping from behind the caliper.. Brake line looks fine.. not wet.. connection not wet.. I couldn't see the leak.. I removed the caliper and brakes and around the plungers look dry.. Everything inside looks dry..? :confused: I pumped the peddle again and the outer bleeder spits fluid. I tightend up all the bleeders... pushed the pedle and no drips.. :confused: I put it back together and pumped the pedle and no leaks so I'm not sure what was happening.. I had to do some work work :lol: so I'll check again in a few..

I sprayed everything with brake cleaner include the engine compartment where the master overflowed.. That should clean off the brake fluid.. right?


[Modified by Koz, 10:40 AM 3/29/2002]

 

Well, since you got fluid to spit out of the outer bleeder, remove the top of the master cylinder, and let it run for a few minutes. You will see flow interuptions meaning that air is escaping. Then follow the instructions above.

dl

 

Thanks for your help.. I think my problem was that it was air blocked. I opened the bleaders and got a steady ooz of fluid. Once I got the fluid to move it seemed to flow pretty easily. Thanks again for the help! :cheers: